Functionalization of Semiconductor Surfaces

CHAPTER 11

Formation of Organic Monolayers Through Wet Chemistry

DAMIEN AUREAU AND YVES J. CHABAL

11.1 INTRODUCTION, MOTIVATION, AND SCOPE OF CHAPTER

11.1.1 Background

Wet chemical cleaning has always been an intrinsic part of semiconductor processing [1,2], but only relatively recently has wet chemistry been used to modify semiconductor surfaces for sensitive applications. Wet chemical functionalization is attractive because it can be performed in reasonably manageable environments and is scalable. Wet chemical cleaning, for instance, which constitutes ~30% of silicon processing in microelectronics, can be performed for entire cassettes of wafers in regular clean rooms. Clean chemicals have also been developed for such large-scale use. In general, wet chemical processing is simpler and more versatile than ultrahigh vacuum (UHV) methods, and can often lead to more perfect surfaces than what can be achieved in UHV [3–8].

Silicon has been central to the microelectronics industry for one main reason. Its oxide is stable and the interface between silicon and its oxide is electrically much better than for any other semiconductor surface, in particular germanium [9]. It is therefore not surprising that the early work on silicon surface functionalization has focused on attaching organic molecules to silicon oxide, using silanization for instance [10]. Typically, silanization is based on hydrolyzing molecules such as triethoxysilanes or trichlorosilanes with hydroxyl-terminated silicon ...